Improvement in beam-compasses



M. TDU'LMIN.

Beam Compasses. No. 142,823. Patented September16,187 3.

m? 21 eases,

UNITED STATES PATENT OFFICE.

MORTON TOULMIN, OF NEW ORLEANS, LOUISIANA.

IMPROVEMENT IN BEAM-COMPASSES- Specification forming part of Letters Patent N0.142,823, dated September 16, 1873 application filed June 4, 1873.

To all whom it may concern:

Be it known that I, MORTON TOULMIN, of New Orleans, State of Louisiana, have invented an Improved Drawing-Instrument, of which the following is a specification:

The object of my invention is to construct an instrument in the form of a beam drawingcompass, for the use of draftsmen and others, so as to combine the different instruments used for drawing lines, circles, and spirals in one instrument, and to admit its adjustment while in use by the operator.

My instrument is composed of two parallel bars or rods, fixed at one end to a cross bar or head, having between and parallel to them a screw fastened also to the head, on all which the drafting pens or pencils slide. The positions of the pens and handle are adjusted by means of nuts revolving upon the screw, and embraced in slots cut through the stocks of the pencil, pen, and needle points, respectively.

Figure l is a general view of the instrument, comprising a needle-point, with stock and handle and two drawing-pens attached. Fig. 2 is a detached View of the needle, which is so arranged as to admit of a very minute change in the position of the point. Fig. 3 shows detached views of the bolt and nut moving the needle-point. Fig. 4 is a modification of the instrument shown in Fig. 1.

Ais the handle 5 B B, the parallel bars; O, the head; D, the stock of the handle; E, the screw; F F, the drawing-pens, or their equivalents, through the stocks of which are holes fitting the bars B B; G is the needle; h, the eye of the bolt m, passing through the nut 70, by which the needle G is bent or sprung, causing a deflection of its point p. n n are the nuts in the slots 8 s of the stocks of the drawing-pens, traversing the screw E, and moving them at will in either direction.

It will be seen that any number of concentric circles may be drawn at the same time by increasing the number of pens or pencils upon the bars. Parallel straight lines may also be drawn, either with or without the needle-point bearing against the ruler, and by revolving the nut 11. upon the pen in use successive lines may be drawn at distances, accurately gaged by the number of turns given to the nut 01. A spiral line may also be formed by giving a continuous motion to the nut 42, increasing the radius of the curve by a constant or varying amount.

Either of the pens may be used with the handle A, forming an ordinary right-line pen, by substituting it for the set-screw at the top of the pen-stock.

By changing one of the pens for a needlepoint this instrument is peculiarly adapted for setting off distances, and by means of the spring-needle G the most minute spaces may be laid down or transferred. This needle is fixed in two bearings, b 1), near its upper and lower ends. In the space between the two bearings the needle is clasped by an eye or loop, h, of a screw-bolt, m, and the latter, being moved by turning the nut is, bends or springs the needle in the middle, causing a reverse deflection of the point. For purposes where very minute changes in the position of the point are necessary-as in spacing divisions on the circumference of a circle, dividing a line into a given number of parts, and transferring distances forlaying out map projections, where minute accuracy is required-this device will be found exceedingly useful.

Combining, as it does, all the requisites for the ordinary work of a complete set of drawin g-instruments, it is easily handled, adjusted, and operated, and has the advantage of being furnished at a very much smaller comparative cost.

I claim+ 1. The arrangement, in a beam draftingcompass, of the bars 13 B, stationary screw E, and two or more drafting-pens, or their equivalents, each adjustable, back and forth, upon the bars by means of nutsn n in the slots 8 8, working upon the screw, all substantially as set forth.

2. The needle G, arranged as shown and described, with two bearings, 12 11, between which the needle is embraced by the eye h of a bolt, m, extending through the stock I), and by which the middle of the needle is sprung as desired, causing an opposite defiection of the point 10 below the lower bearing, all substantially as shown and described.

MORTON TOULMIN.

Witnesses:

(1H. PooLE, EnM. F. BRowN. 

